In medical imaging or animal research applications, high frequency ultrasound is used to study the details of fine tissue structures and moving objects in a small area of interest. For example, in the field of cancer research, high frequency ultrasound is used to study the effects of drugs and other treatments on laboratory animals such as mice. Most diagnostic ultrasound systems utilize an array of 64, 128, 256 or more ultrasound transducer elements that are formed of a piezo-electric material. The transducer elements generate ultrasonic waves when excited with a voltage pulse and produce electronic signals when exposed to the corresponding echo signals.
As the frequency of the ultrasound systems increase, the sizes of individual transducer elements within an array decrease. For example, a 40 MHz transducer has a typical element pitch of 38-45 μM (microns), while a 60 MHz transducer has a typical element pitch of 25-30 microns. As a comparison, an average human hair has a diameter of approximately 80 microns. At this scale, one of the biggest challenges associated with manufacturing high frequency ultrasound transducers is connecting the leads that carry electrical signals to and from the elements of the transducer array. As will be understood by those of ordinary skill in the art, each transducer element must be electrically connected to a separate lead in order to allow a voltage signal to be placed across the element during signal transmission and to carry a voltage signal that is produced when the element is exposed to a returning ultrasonic echo signal. At these small dimensions, the challenge of aligning and bonding the individual electrical leads to the transducer elements is time consuming and prone to error.
Given these problems, there is a need for an improved method of creating a high frequency ultrasound transducer with electrical leads that are connected to individual transducer elements.